Beginning in the mid to late 1960's and continuing to the present, mortality rates attributed to coronary heart disease in the United States have exhibited a consistent decline. Due to the paucity of population-based data examining the potential contributors to this decline, a population-based study in the setting of the Worcester, Massachusetts, standard metropolitan statistical area (SMSA) is proposed to further extend preliminary findings obtained in a previous pilot study of the years 1975, 1978, 1981 and 1984. The objectives of this community-wide study are to examine recent (1986, 1988 and 1990) as well as prior (1975, 1978, 1981, 1984) time trends in the incidence rates of acute myocardial infarction and out-of-hospital coronary heart disease death as well as changes in the in-hospital and long-term case-fatality rates of acute myocardial infarction. Temporal trends in the theraputic management and diagnostic work-up of patients hospitalized with acute myocardial infarction will also be examined. To accomplish these objectives the study will be divided into three phases. In Phase I, all new and recurrent episodes of acute myocardial infarction occurring among residents of the Worceser SMSA during the years 1986, 1988 and 1990 will be identified from all sixteen acute general hospitals. The medical records of these patients will then be individually reviewed for validation and abstraction purposes. A review of records of additional hospitalizations and a state-wide search of death certificates will also be carried out in order to examine the long-term survival status of discharged hospital patients from each of the proposed study years 1986, 1988 and 1990 as well as those of previous pilot years. In Phase II of this study, death certificates of Worcester SMSA residents for the years 1986, 1988 and 1990 will be examined in order to identify cases of out-of-hospital coronary heart disease death. A random sample of next-of-kin interviews of patients identified through this search will be conducted for the recent years under study in order to determine the circumstances of the death. In the final phase, census data will be collected from appropriate sources in order that the various incidence and case-fatality rates can be calculated. The results from this community-wide investigation will provide a temporal picture of coronary heart disease as it affects the residents of a large metropolitan area and provide insights into the role of primary and secondary preventive efforts.